Computer-assisted Infrared Analysis of Heterogeneous Works of Art

In this paper a simple elaboration of the infrared spectra of heterogeneous materials is outlined. The data processing method, based on the least-squares solution of overdetermined systems, allows the semiquantitative analysis of mixtures in terms of the spectra of their components. An application of the data processing logic to a twoand threecomponents mixture is shown, but the method can be applied to more components with no difficulty. The proposed algorithm requires few instructions in a spreadsheet macro and can be applied fruitfully to the Fourier transform infrared spectra of materials of historic and artistic value, which generally do not allow chemical manipulation for the analysis of the samples.